[vsnet-grb-info 7548] GRB 090407: Swift UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9106
SUBJECT: GRB 090407: Swift UVOT Upper Limits
DATE:    09/04/07 21:34:44 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R.  Oates (MSSL-UCL) and H. Ziaeepour (MSSL-UCL) report on behalf  
of the Swift/UVOT team:

The Swift/UVOT began observing the field of GRB 090407 98 s
after the BAT trigger (Ziaeepour et al., GCN Circ. 9101). No
optical afterglow is detected in the initial UVOT exposures at
the refined position of the X-ray afterglow (Evans et al., GCN Circ.  
9105).

The 3 sigma upper limits for the finding chart (fc) and summed
exposures are reported below.

Filter    T_start (s) T_stop  Exposure      Mag/3UL
------------------------------------------------------------
white fc    98          248          147         <20.50
u fc	          310       559          246         <19.89
white        590       2050        303         <21.04
v               640        5550        352         <19.25
u    	         713        2001        136         <19.61
b    	         565        2026        156         <19.99
uvw1       689	        1977        136         <19.35
uvm2       664        5607        207         <19.49
uvw2       615	        2071        170         <19.74
	

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} =  0.40 mag (Schlegel et al.,
1998, ApJS, 500, 525).  The photometry is on the UVOT photometric system
described in Poole et al. (2008, MNRAS, 383,627).